1. Field of the Invention
The present invention relates to an input apparatus for entering data, command, etc. in a portable type electronic instrument such as an electronic pocketbook.
2. Description of the Background Art
In recent years, in conjunction with the considerable reduction of sizes of the electronic devices, the portable type electronic devices such as a portable electronic pocketbook have been developed for practical use and becoming popular. Such a portable type electronic device can be operated while holding it in hand or placing it on lap, so that it is operable even in a circumstances in which an ample space for firmly settling it cannot be found, and consequently the potential for its utilization has been increased considerably. As a result, there is an expectation for the utilization of such a portable type electronic device for the so called mobile computing in which a computing device can be carried around all the times and used whenever necessary at wide range of locations.
On the other hand, such a portable type electronic device is associated with a problem that it is difficult to secure the satisfactory handling of the device as it is quite compact and to be operated without being firmly fixed. For instance, in a case of operating it while holding it in hand, there are greater chances for making erroneous operations due to the vibration of the device held in hand. In particular, when the input apparatus adopted in such a portable type electronic device is of a type for entering the handwriting characters or of a type requiring a continuous input operation such as a slide control type, it is prone to have the unintentional movements due to the vibration mixed up with the intended input operations, such that it becomes difficult to separate out the data entered by the intended input operations alone. Moreover, in a case of displaying the data entered by the input operation, the erroneous data entered by the unintentional movements due to the vibration are also going to be displayed, and such erroneous data display may interfere with the correct operations of the device.
In addition, there is a general trend to make such a portable type electronic device even more compact so that the operation units to be operated by a user are also becoming increasingly compact, and consequently there are greater chances for making erroneous operations as there are greater chances for a user to touch the uninterested operation units accidentally.
In the conventional portable type electronic device, such erroneous operations are detected by the scheme in which the propriety of each operation in the input operation procedure is judged by matching with the prescribed checking list. In this scheme, the input operation procedure is detected by the same input means as that used for entering the data.
Now, the erroneous operations occurring in the portable type electronic device can be generally classified into the following two cases. One is a case in which the content entered by the input operation is erroneous despite of the fact that the operation itself is a proper one according to the correct input operation procedure as the user correctly recognizes the input operation procedure. The other one is a case of the unintentional operation made by the user due to the vibration of the device or some other causes.
In order to detect the erroneous operation of the former case, there is a need to utilize a checking list including not Just the correct input operation procedure itself but also the knowledge concerning its semantic contents. Such an error detection scheme requires a highly complicated matching process and it is not easy to compile all the necessary knowledge in advance, so that the use of this scheme is limited to a case in which the highly sophisticated judgement of the errors is demanded regardless of the cost required for its implementation.
As for the detection of the erroneous operation of the latter case, when the input operation procedure is standardized, it can be realized relatively easily by checking whether each operation of the input operation procedure is enlisted on the checking list which contains the entire correct input operation procedure. However, when the types of the possible operations are numerous or when the non-standardized input operations are involved, either the matching process becomes difficult as the checking list takes an enormous size or the construction of the checking list itself becomes practically impossible so that the effective detection of the erroneous operation is not feasible.
Thus, in the conventional portable type electronic device, the correct input operations and the erroneous input operations can be distinguished from each other only in very limited cases.
In particular, in the conventional erroneous operation detection scheme, the judgement of the intentional correct input operation and the unintentional erroneous input operation is based on the analysis of the input data, so that there have been cases in which it cannot be helped but judging it as the intended input operation no matter what it really is, as long as the entered input data is in compliance with the prescribed correct input operation procedure.